There are some countries in which the "Daylight Savings Time" was introduced and in such a country, a time adjustment is mandated twice a year to meet the time shift due to the Daylight Savings Time. During the Daylight Savings Time period in such a country, it is required to adjust the time/date information (i.e., Year/Month/Day/Time) of the communication device such as a facsimile machine from the time/date data based on the standard time to the time/date based on the Daylight Savings Time period.
In an ordinary case, such time adjustment due to the Daylight Savings Time (hereinafter referred to as "DST" for short) is carried out by the operator. In some other case, there exists a facsimile, representing the communication device of this invention, has a function to adjust the time change due to the DST. Such a facsimile has a data storage memory for storing time/date information of the DST including a beginning date of the DST and an end date of the DST and means for automatically changing the time/date information from the one according to the standard time of the particular region (or a country) to the time/date information according to DST period when the region enters to the DST period and automatically switch back to the time/date according to the standard time when the DST period ends.
In the former conventional communication device described in the above, the user has to manually adjust the time/date information of the device at the beginning of the DST period and the end of the period. Thus the adjustment itself by the user could be a cumbersome task and moreover if the user neglects such adjustment, the wrong time/date information appears on the display of the device.
Even with the latter mentioned facsimile device as a prior art technology having a function of automatic time adjustment due to the DST, if the device still has to rely on the user's input data including a beginning date of the DST and an end date of the DST, very similar problems as described will result.
If, however, the latter mentioned device stores in advance information regarding the beginning and the end of the DST period in all the regions and countries employing DST, needlessly large memory is required for storing the information as practically speaking only one set of data is needed for the facsimile machine; thus the rest of the stored data would never be used unless the machine was transferred to the other regions.